FAMILY FORMICARIIDAE 207 



Description. — Length 125-150 mm. Adult male; crown, including 

 lores, slate to slate-black; hindneck usually grayer; upper back 

 brownish oHve ; lower back, rump, and upper tail coverts chestnut to 

 chestnut-brown ; feather bases in center of back clear white, bordered 

 by black, the area usually completely concealed ; anterior line of lesser 

 wing coverts pure white ; others black, with tips white ; greater 

 coverts spotted at the tip with rufous ; chin, malar area, and foreneck 

 black ; side of head, sides, breast, and upper abdomen slate to slate- 

 gray ; upper breast spotted irregularly and indistinctly with black ; 

 posterior sides, flanks, and under tail coverts Vandyke brown ; under 

 wing coverts white barred with black. 



Adult female, upper surface like male, but with crown somewhat 

 grayer; wings with rufous spots more abundant; concealed white on 

 back less in extent ; throat black, heavily spotted with white. 



A male, from Armila, San Bias, March 4, 1963, had the iris red ; 

 maxilla and mandibular rami black ; rest of mandible neutral gray ; 

 tarsus, toes, and claws neutral gray. 



A female from the Rio Tacarcuna, Darien, March 10, 1964, had 

 the iris bright red ; maxilla black ; mandible dusky neutral gray ; 

 tarsus, toes, and claws rather dark neutral gray. 



Measurements. — Males (10 from Province of Panama, Colon, 

 Darien, and San Bias), wing 60.0-66.0 (63.5), tail 39.8-45.6 (42.7, 

 average of 9), culmen from base 18.8-21.0 (19.9), tarsus 26.0-27.0 

 (26.8) mm. 



Females (10 from Veraguas, Province of Panama, and Darien), 

 wing 59.7-64.8 (62.7), tail 40.0-49.2 (43.7), culmen from base 18.3- 

 20.1 (19.1), tarsus 25.1-26.9 (26.2) mm. 



Resident. Uncommon, in undergrowth in heavy forest. Recorded 

 in scattered localities on the Pacific slope from Veraguas to Darien; 

 on the Caribbean side from eastern Colon, Canal Zone, eastern San 

 Bias, and one record from Rio Calovevora in northern Veraguas. 



This interesting species was described by Salvin from a specimen 

 taken in 1864 by Enrique Arce at Tucurrique, on the Caribbean slope 

 of Costa Rica. Later Salvin (Proc. Zool. Soc. London, 1867, p. 145) 

 recorded a female from Santa Fe, Veraguas, also collected by Arce. 

 Benson secured others there at elevations of 500 to 760 meters from 

 March 2 to April 13, 1925. J. R. Karr found a pair on the Rio Men- 

 doza in the Navy Pipeline area in July 1969. Goldman collected a pair 

 on Cerro Azul, eastern Province of Panama, on March 23, 1911, and 

 a male on Cerro Bruja, eastern Colon, June 7 of the same year. 

 Thomas Barbour and W. S. Brooks found this ant-shrike fairly com- 

 mon on Cerro Sapo, Darien, in April 1922. Griscom (Bull. Mus. 



